1. Field of the Invention
The present invention relates to an air intake port system for an internal combustion engine cylinder head.
2. Background Information
Internal combustion engines, such as gasoline automobile engines, have been provided with air intake systems having multiple air intake ports adapted to generate high in-cylinder air swirl in attempts to improve combustion, fuel economy, and emissions. Such air intake systems, however, generally exhibit lower air mass flow efficiency as a result of increased air flow resistance attributable to the particular air intake port designs used heretofore. In particular, high in-cylinder air swirl traditionally has been generated by bending and twisting of the air intake ports to effect a generally helical flow of air about the axis of at least one of the intake valves. However, loss of in-cylinder swirl motion at lower power regimes of engine operation, such as at engine idling, has been so severe in some situations as to require a port deactivating device to deactivate one of the air intake ports in order to maintain some in-cylinder swirl. These port deactivation devices typically reduce flow efficiency even further.
Objects of the present invention are to provide an internal combustion engine cylinder head with one or more air intake ports arranged and configured in a manner to overcome the above-discussed shortcomings of previous air intake port systems and provide effective in-cylinder swirl and air mass flow rates at all regimes of engine operations such that there is no need for a port deactivating device.